JPS6033282B2 - Voltage nonlinear resistor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voltage nonlinear resistor made of a sintered body mainly composed of zinc oxide.

In recent years, zinc oxide has been used as the main ingredient, and bismuth oxide, manganese oxide, cobalt oxide, antimony oxide, and as necessary, nickel oxide, chromium oxide, silicon oxide, boron oxide, lead oxide, magnesium oxide, aluminum oxide, etc. have been added. Voltage non-linear resistors are made of sintered bodies molded and fired, or sintered bodies made mainly of zinc oxide with additions of lanthanum oxide, braseodymium oxide, samarium oxide, neodymium oxide, cobalt oxide, manganese oxide, etc. The body is widely used in voltage stabilizing elements, surge absorbers, arresters, etc.

When this voltage nonlinear resistor is used as a high voltage surge absorber or arrester, its side surfaces are coated with a high resistance layer mainly made of zinc antimonate and zinc silicate, and then The high-resistance layer is usually coated with a glass layer to prevent surface staining. FIG. 1 shows the structure of a voltage nonlinear resistor.

In the figure, 1 is a sintered compact mainly composed of zinc oxide, 2 is an electrode provided on the main surface of the sintered compact, 3 is a high resistance layer provided on the side surface, and 4
is a glass layer. Here, the high resistance layer is antimony oxide,
Because it is a sintered body layer created by reacting silicon oxide with zinc oxide at high temperatures, it has high resistance and has good adhesion to zinc oxide-based nonlinear sintered bodies, but the surface is extremely uneven. The problem is that it is easy to get dirty and it is difficult to remove the dirt that adheres to it. On the other hand, the structure shown in Figure 1 has the characteristic that the surface of the glass layer is smooth and difficult to stain. In the secondary voltage nonlinear resistor, the coating glass layer is (1}
Similar thermal expansion coefficient to zinc oxide sintered body, '2
}Good green resistance,'3}Easy to handle,
For this reason, lead borosilicate glass with a thermal expansion coefficient of 60-85 x 10-7/°C, or lead-zinc borosilicate glass with a similar thermal expansion coefficient, and titanium oxide oxide steel or aluminum oxide added to these are used. glass is commonly used. However, in conventional voltage nonlinear resistors, the adhesion strength between the high resistance layer and the glass layer is weak, and thermal cycling can cause delamination between the two and microcracks in the glass layer. However, there was a problem in that the impulse withstand capacity was reduced. The present invention aims to eliminate the drawbacks of the prior art described above and provide a voltage nonlinear resistor that is resistant to thermal cycles. The voltage nonlinear resistor of the present invention is composed of a sintered body mainly composed of zinc oxide, and is provided at least on the side surface of the sintered body with a high resistance layer mainly composed of zinc antimonate and zinc silicate. The resistor having a lead borosilicate glass layer is characterized in that the lead borosilicate glass contains antimony oxide and zinc oxide.

As a result of various studies conducted by the present inventors, it was found that the adhesion between the zinc antimonate layer in the high resistance layer and the glass layer is particularly poor.
It was found that separation occurs, and that if antimony oxide and zinc oxide are dispersed in the glass layer, the adhesion strength between the two can be greatly improved.

That is, when the glass of the present invention is deposited on a high-resistance layer and baked, silicon oxide and zinc oxide in the glass react with zinc silicate, and antimony oxide and zinc oxide react with zinc antimonate (interdiffusion). , the adhesion between the high-resistance layer and the glass layer is improved, and a voltage nonlinear resistor that is resistant to thermal cycles can be realized. The amount of antimony oxide in the glass is preferably within the range of 1 to 1% by weight. If the amount of antimony oxide is less than this range, the adhesion with the high resistance layer will be insufficient. On the other hand, if the amount of antimony oxide is too large, the glass layer will be distorted due to the difference in thermal expansion coefficient between antimony oxide and zinc oxide sintered body: 196 x 10-7/℃ for the former and about 70 x 70-7/℃ for the latter. Cracks and microcracks occur, resulting in a decrease in the dielectric strength of the glass and a decrease in impulse resistance. The amount of zinc oxide in the glass is preferably in the range of 4 to 3% by weight.

If the amount of zinc oxide is too large than this range, the impulse withstand capacity will be reduced due to the generation of microcracks, and if it is too small, the adhesion with the high resistance layer will deteriorate. The amount of silicon oxide in the glass is preferably in the range of 2 to 25% by weight.

If the amount of silicon oxide is too small, the moisture resistance of the glass will deteriorate and its dielectric strength will drop due to moisture in the air, and if it is too large, the baking temperature of the glass will become too high, causing a voltage drop during baking. This has disadvantages in that the characteristics of the linear resistor are likely to change, and the glass is likely to break during thermal cycling. The amounts of lead oxide and boron oxide in the glass are preferably in the range of 45 to 85% by weight and 3 to 2% by weight, respectively.

If there are too many of these, the moisture resistance of the glass will deteriorate.
Furthermore, the coefficient of thermal expansion becomes too large, resulting in the glass layer being susceptible to cracking during thermal cycling. On the other hand, if the amount of these is too small, a high temperature is required to heat the glass, and the coefficient of thermal expansion becomes too small, making it easy for the glass layer to crack during thermal cycling. And the content of the three components, silicon oxide, lead oxide and boron oxide, is
3-25% by weight, 45-75% by weight, and 3% by weight, respectively.
A range of 15% by weight is particularly desirable.

In addition, as described later, the amounts of lead oxide, boron oxide, and silicon oxide in the glass are 45 to 75% by weight, and 3 to 3% by weight, respectively.
15% by weight and a range of 3 to 25% by weight are particularly desirable.

- From the baking temperature of glass to the minimum operating temperature of a nonlinear resistor
It is not possible to completely match the coefficient of thermal expansion of glass to that of the zinc oxide burnt stripe over a wide temperature range of about 30°C.

Therefore, when using a non-linear resistor in a particularly wide temperature range, tin oxide of 0.4 to 1% by weight in the glass,
Glass can be made into crystallized glass by adding 1 to 10% by weight of aluminum oxide, or filled glass can be made by adding 5 to 3% by weight of zirconium oxide as a filler.
It is necessary to prevent cracks in the glass layer. Note that if the amount of tin oxide, aluminum oxide, or zirconium oxide added is less than the above range, it will not be sufficiently effective in preventing cracks in the glass, and if the amount added is too large, the impact resistance of the glass will be reduced due to the effects of microcracks, etc. resulting in a deterioration. The voltage non-linear resistor to which the present invention is applied is a dawn striped material containing zinc oxide as a main component and 0.01 to 10 mol% of each of bismuth oxide, manganese oxide, and cobalt oxide, or as required. 0.01 each
Scale bodies or zinc oxide containing at least one component of ~10 mol% of antimony oxide, nickel oxide, chromium oxide, silicon oxide, boron oxide, lead oxide, aluminum oxide, magnesium oxide, silver oxide, etc. The main components are 0.01 to 10 mol% of lanthanum oxide,
Contains at least one component of praseodymium oxide, samarium oxide, neodymium oxide, dysprosium oxide, thulium oxide, etc., and further contains at least one of cobalt oxide and manganese oxide in an amount of 0.01 to 10 mol% each.
It is a sintered body containing components. In order to prevent creeping flashover, it is necessary to provide a glass layer or a high resistance layer on at least the side surface of the bran aggregate, as shown in the figure.

It goes without saying that these layers may be provided even on the main surface where the electrodes are provided, if necessary. Although the present invention will be explained below with reference to Examples, the effects of the present invention are not limited to these Examples, and even if small amounts of other additives such as various metal fluorides are contained in the glass. Needless to say, it's a good thing. % in text is weight %
It is. Example 1 Bi20 to Zn0785.3g
323.3g, C.

2038.3g, MnC035.8g, Sb20
329.2g, Cr2037.6g, Ni07.
5g, Si023.0g, &030.8g, and AI
(N03)30. Males were added and mixed for one field hour using a pole mill.

Add 10% of 2% polyvinyl alcohol aqueous solution to this raw material powder and granulate it, molding pressure 750k9/me and shape 12 skin. It was molded into a x5 willow t-shirt. After heat-treating this molded body under the conditions of raising/lowering temperature rate 100oC/h and holding for 900002 hours, Bi203112g and Sb
An oxide paste obtained by kneading 203,175 g, Si02,130 g, ethyl cellulose octacid, 600 g of butyl carbitol, and 150 g of butyl acetate was mixed with 100-20 g of oxide paste.
It was applied to a thickness of 0 French m. Next, this temperature rise/fall rate is 10
It was fired under the conditions of 0°C/h and held at 1200°C for 5 hours. In the firing process, Bi2 in the oxide paste
Q diffuses, and Sb203 and Si02 react with ZNO to form Zn7SQ0i2 and Z~
A high resistance layer 3 mainly made of Si04 was formed. At this stage, the surface of the element is easily soiled during the impulse test due to the extremely uneven surface of the element. The problem was that it was prone to creeping flashover. Next, glass (Pb055) is attached to the side of the element.
%, B038%, Si027%, Zn025%, Sb2
A glass paste obtained by kneading 400 g of ethyl cellulose, 11 g of ethyl cellulose, 7 g of butyl carbitol, and 30 g of butyl acetate was mixed to a thickness of 10 g.
It was applied to a thickness of 0 to 200 mm and heat treated in air at 600 oo for 10 minutes (temperature rise/fall rate 200 qo/h).

As a result, an element having a structure in which the surface of the high resistance layer 3 was covered with the glass layer 4 was obtained. Finally, both principal surfaces of the element were polished flat, and AI electrodes 2 were sprayed on both crown surfaces to obtain an element having the structure shown in the figure. The side surfaces of the resulting device were smooth and free of dirt.
Furthermore, since it has excellent moisture resistance, there were no problems such as a decrease in impulse resistance during device handling. In addition, the adhesion between the glass layer and the element is good,
Even after repeating the heat cycle from -30°C to 80°C 1000 times, there were no problems such as peeling of the glass layer, cracking, or changes in properties. On the other hand, for comparison, using the same method, a glass without SQ03 (Pb057%, B20
38.5%, Si027.5%, Zn026%, AI2
031% containing glass, or PO055%, &038
%, Si027%, Zn025%, AI2035%) is coated and baked, the adhesion strength between the glass and the element is weak, and repeated thermal cycles cause problems such as reduced impulse resistance. occured.

Example 2 Zn0785.3g Bi20346.6g,
C.

20316.6g, MnC035.8g, Sb2
0329.2g, Cr2037.6g, Si02
9. Female, B2Q3. Him “Ni07. Rudder, AI (NQ) 3
Add 0.1g and mix, granulate, and granulate in the same manner as in Example 1.
Molding, heat treatment, oxide paste coating, and firing.

The dimensions of the fired element are 3 pieces x 3 pieces. next,
Glass pastes were prepared in the same manner as in Example 1 using glasses of various compositions, and this was applied to the side surface of the element.
0-65030 and its characteristics were investigated. Therefore, it is thought that those whose green resistance is ○ can be used at high temperatures, and those whose green resistance is Δ can be used by incorporating them into glass, such as in arresters. The table shows the glass composition used and the results of examining device characteristics.

Heat resistance cycle test judgment criteria in the table: ×× Cracks occurred in the glass layer during slow cooling to room temperature after competition. × Heat cycle test - Impulse resistance decreases by 300 times.

○ No change in characteristics due to the above thermal cycle test.

Humidity resistance property judgment criteria × If the device is left immersed in water, glass elution or a decrease in impulse resistance is observed.

△ When the element is boiled in water, elution of glass or a decrease in impulse resistance is observed. ○ Impulse withstand capacity did not change as a result of the above test.

Therefore, it is considered that the elements marked with a moisture resistance characteristic of ◯ can be used at high temperatures, and the elements marked with a △ mark can be used by being incorporated into glass, such as in an arrester. From the table, Sb2
Glass that does not contain 03 (Reference Examples 1 and 2), glass that contains it but has a small content (No. 1), glass that does not contain Zn0 or Si
Glasses (Nos. 6 and 10) with a small amount of 02 content showed a large decrease in impulse withstand capacity after thermal cycling;
b203, Zn○, Si02, AI203, Sn02,
There are too many Zr02 etc. (No. 5, 9, 13, 27,
32 and 37), it can be seen that cracks are likely to occur in the glass during baking.

Also, there may be too few 2 in S (No. 10), or Pbo
It can be seen that when there is too much Pbo or &03 (No. 18 and 19), the moisture resistance of the glass deteriorates, and conversely, when there is too little Pbo or &03 (No. 9 and 14), the heat cycle resistance characteristics deteriorate. . The glass that has particularly excellent heat cycle resistance and green resistance is 45≦Pb0≦75%,
3≦B203≦15%, 3≦Si02≦25%, 1≦S
The range is Q03≦10%, 4≦Zn0 and 30%. Also, 1-10% AI203, 0.4-10% Sn0
When the glass contains 2.5 to 30% ZrO2, etc., the heat cycle resistance of the glass is extremely excellent. Example
3 Zn0785.3g, Bi20323.3g,
C.

2038.3g, MnC035. The base was mixed, molded, coated with oxide paste, and fired in the same manner as in Example 1.

The dimensions of the element after firing are 56 sides x 2 sides. Next, add this to Hisinori o. 60 pieces of glass powder of No. 38 were immersed in a solution of ethyl cellulose (1 rudder) dispersed in a trichlene solution (800 ml), dried, and then baked at 500 oo for 10 minutes.
After that, the two royal faces were polished and electrodes were attached. 4 for this element
No creepage flashover occurred even when 130 kA of impulse was applied for 10 ms.

Further, even after repeated heat cycle tests of 130280 pm, the impulse withstand capacity did not decrease. On the other hand, 7/10 of the elements with non-glazed elements had an impulse of 100% due to surface contamination during the polishing process and electrode attachment process.
Creepage flashover occurred when kA current was applied.

Also, No. of the table. Instead of 38, reference example 1 or 2
When using glass of
Impulse tolerance is 10 in 0 or 6/10 elements.
A problem occurred in that the voltage decreased to 0 kA or less.

Example 4 Zn0485g, N also ○3 or S
Example 3 m20310.0g, Co2035.0g
Mixing, granulation, molding, application of oxide paste, and firing were performed in the same manner as above. Next, in the same manner as in Example 1, the No. 3
A paste consisting of 9 glasses was applied. These elements also had an impulse withstand capacity of 130 kA, did not cause surface flashover, and had excellent heat cycle resistance. As explained above, the zinc oxide-based voltage nonlinear resistor of the present invention has the following advantages.

{a' Creepage flashover is less likely to occur and impulse withstand capacity is large. 'b) Excellent green resistance and heat cycle resistance.

‘c’ The sides are smooth and dirty and ‘difficult’.

[Brief explanation of the drawing]

The figure is a sectional view showing the structure of the voltage non-wire resistor of the present invention. 1... Zinc oxide based sintered twill body, 2... Electrode, 3... High resistance layer, 4... Glass coating layer.

Claims (1)

[Scope of Claims] 1. A lead borosilicate glass layer made of a sintered body mainly composed of zinc oxide, and provided on at least its side surface with a high-resistance layer mainly composed of zinc antimonate and zinc silicate. 1. A voltage nonlinear resistor characterized in that the lead borosilicate glass layer contains antimony oxide and zinc oxide. 2. The voltage nonlinear resistor according to claim 1, wherein the glass is lead borosilicate glass containing 1 to 10% by weight of antimony oxide and 4 to 30% by weight of zinc oxide. 3 The glass contains 2-25% by weight of silicon oxide and 4% by weight of lead oxide.
The voltage nonlinear resistor according to claim 1 or 2, which is lead borosilicate glass containing 5 to 85% by weight and 3 to 20% by weight of boron oxide. 4. The voltage non-conductor according to claim 1, 2 or 3, wherein the glass is lead borosilicate glass containing 0.4 to 10% by weight of tin oxide or 1 to 10% by weight of aluminum oxide. Linear resistor. 5. The voltage nonlinear resistor according to claim 1, 2, 3, or 4, wherein the glass is lead borosilicate glass containing 5 to 30% by weight of zirconium oxide.